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RE: [10GBASE-T] RE: EMI Discussion




Hi Brad,

I think you meant to say "Task Force" down there. Did you mean Study group?

Yes I agree that meeting FCC A is a good objective that would drive the
investigation of this issue to completion.

My only conundrum on this issue is understanding the balance between "broad
market potential" which I believe depends upon CAT-5e and CAT-6 cables and
"technical feasibility" which I believe depends upon some
assurance that a high-speed line code running at 833Mbd will not by its
nature violate FCC requirements on UTP components that were not designed for
that frequency range.

I think that keeping CAT-5e and CAT-6 cables as an objective is the right
approach, so that leaves us to gain some confidence in being able to obtain
FCC compliance on those cables. The amount of data required
to do that is substantially below the amount required to complete the spec.
I think that limiting the scope of the investigation to what I had discussed
earlier, obtaining market data to understand which components
are broadly installed, then doing some testing on those components is
sufficient to complete those objectives.

Another possible angle would be to restrict the application to patch cords
only for data center/wiring closet applications and if that gets broad
enough capture of the market, move forward and expand the study down the
road to include x-connects, patch-panels and wall jacks. I have very low
concern about the cable itself, its those darned connectors that give me
concerns. This latter approach, if the marketing folks believe it will be
viable, would substantially reduce my concerns about EMI feasibility at this
stage.

Dan

> Dan,
> 
> I agree that the Study Group could use more breadth of data, 
> considering
> that both EMI measurements I found (jones_2_0103 and 
> powell_1_0303) have
> been based on unscreened Cat5e cabling.  I also agree that the Study
> Group should take EMI into consideration in selecting 
> proposals to adopt
> for a first draft.
> 
> The question I have is about the best approach.  Personally, I believe
> that creating an objective to "meet FCC Class A requirements" is what
> the Study Group needs at this point in time.  That would 
> place a burden
> on the Study Group to evaluate our cable type and reach objectives
         ^^^^^^^^^^^
         Task Force

> relative to EMI compliance.
> 
> Do you agree with that approach?
> 
> Thanks,
> Brad
> 
> -----Original Message-----
> From: DOVE,DANIEL J (HP-Roseville,ex1) [mailto:dan.dove@hp.com] 
> Sent: Wednesday, August 13, 2003 6:22 PM
> To: Booth, Bradley; stds-802-3-10gbt@ieee.org
> Subject: RE: [10GBASE-T] RE: EMI Discussion
> 
> 
> Hi Brad,
> 
> I think the point of "enough data" is subjective and up to the Study
> group
> to determine.
> 
> While I have reviewed a number of the presentations via the 
> web, I have
> not
> given it nearly as much study as the members of this SG, so I don't
> presume
> to be as qualified to make that judgement as they are. I have 
> seen some
> data
> indicating areas of concern <Cobb July03,Powell May03>, and I have
> reviewed
> the methods and data used to generate the CFI slide as discussed in my
> earlier email, and from that I believe we need more breadth 
> in the data
> to
> understand what percentage of CAT-5e and CAT-6 cables will be
> supportable
> for EMI compliance.
> 
> A lot of the data provided at the URL you reference is 
> focused on signal
> integrity, not EMI. This is fine because there are a lot of signal
> integrity
> challenges to deal with. I think the priority is OK, but am suggesting
> broader EMI investigation for the UTP solutions.
> 
> I won't be at the September meeting, so I was providing my
> recommendation to
> the SG with the hope that some are inspired to present broader based
> data,
> and all will evaluate that data and apply their judgement to 
> the issue. 
> 
> Regards,
> 
> Dan
> 
> > -----Original Message-----
> > From: Booth, Bradley [mailto:bradley.booth@intel.com]
> > Sent: Wednesday, August 13, 2003 1:24 PM
> > To: stds-802-3-10gbt@ieee.org
> > Subject: RE: [10GBASE-T] RE: EMI Discussion
> >
> >
> >
> > I know I don't have the depth of experience that Dan and
> > Geoff have with
> > 802, but I thought it is of interest that ISO/IEC 11801 1st
> > edition was
> > published in 1995, which was the same year as 100BASE-TX 
> was published
> > as a standard.  While I agree that there is a lot of data to be
> > collected, I believe that a large volume of data has been
> > collected and
> > placed on the following web site:
> > http://www.ieee802.org/3/10GBT/public/material/
> >
> > What I'd like to find out from you (Dan and Geoff) is if you believe
> > that all that more data needs to be gathered before the Study Group
> > moves to Task Force or can this be covered if the Study Group
> > creates an
> > objective to meet specific FCC compliance requirements?
> >
> > Thanks,
> > Brad
> >
> > -----Original Message-----
> > From: DOVE,DANIEL J (HP-Roseville,ex1) [mailto:dan.dove@hp.com]
> > Sent: Wednesday, August 13, 2003 2:02 PM
> > To: 'Geoff Thompson'
> > Cc: stds-802-3-10gbt@ieee.org
> > Subject: RE: [10GBASE-T] RE: EMI Discussion
> >
> >
> >
> > Hi Geoff,
> >
> > Good point of clarification.
> >
> > I was not directly involved in that effort. At the time I was
> > working on
> > 802.4 (rf modems,CATV,etc) but I know a number of the folks 
> who worked
> > on it
> > and actually have an original copy of the massive binder 
> full of work
> > done
> > by Bob Conte et al. It was an impressive effort and I think we are
> > looking
> > at something similar here.
> >
> > Regards,
> >
> > Dan
> >
> > > -----Original Message-----
> > > From: Geoff Thompson [mailto:gthompso@nortelnetworks.com]
> > > Sent: Wednesday, August 13, 2003 10:49 AM
> > > To: DOVE,DANIEL J (HP-Roseville,ex1)
> > > Cc: stds-802-3-10gbt@ieee.org
> > > Subject: RE: [10GBASE-T] RE: EMI Discussion
> > >
> > >
> > > Dan-
> > >
> > > At 12:03 PM 8/13/2003 -0400, DOVE,DANIEL J 
> (HP-Roseville,ex1) wrote:
> > > >In the case of 10BASE-T, where we were
> > > >applying high speed (10MHz?) signals to CAT3 wiring which
> > > had been installed
> > > >for phone support, a *huge* quantity of testing was done to
> > > verify signal
> > > >integrity, EMI compatibility, and noise immunity.
> > >
> > > Actually it was not CAT3, The installed base was AT&T DIW
> > (or worse).
> > > We considered DIW as the baseline.
> > > The TIA CAT3 spec was not approved until after the approval
> > > of 10BASE-T.
> > >
> > > Geoff
> > >
> > 
>